[PATCH] tree-optimization/97746 - fix order of mask precision computes

[Richard Biener]

This fixes the order of walking PHIs and stmts for BB mask
precision compute.

Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.

2020-11-09  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/97746
	* tree-vect-patterns.c (vect_determine_precisions): First walk PHIs.

	* gcc.dg/vect/bb-slp-pr97746.c: New testcase.
---
 gcc/testsuite/gcc.dg/vect/bb-slp-pr97746.c | 20 ++++++++++++++++++++
 gcc/tree-vect-patterns.c                   |  8 ++++----
 2 files changed, 24 insertions(+), 4 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/vect/bb-slp-pr97746.c

diff --git a/gcc/testsuite/gcc.dg/vect/bb-slp-pr97746.c b/gcc/testsuite/gcc.dg/vect/bb-slp-pr97746.c
new file mode 100644
index 00000000000..c5a615d1253
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/bb-slp-pr97746.c
@@ -0,0 +1,20 @@
+/* { dg-do compile } */
+
+int a, b;
+short c;
+
+extern void f (short*);
+
+void d()
+{
+  short e[2] = {0, 0};
+  while (a)
+    {
+      f(e);
+      int g = 0 || a, h = 8 && c;
+      short i = c;
+      c = h & g;
+      if (b)
+	b = g || i;
+    }
+}
diff --git a/gcc/tree-vect-patterns.c b/gcc/tree-vect-patterns.c
index eefa7cf6799..f68a87e05ed 100644
--- a/gcc/tree-vect-patterns.c
+++ b/gcc/tree-vect-patterns.c
@@ -5182,15 +5182,15 @@ vect_determine_precisions (vec_info *vinfo)
       for (unsigned i = 0; i < bb_vinfo->bbs.length (); ++i)
 	{
 	  basic_block bb = bb_vinfo->bbs[i];
-	  for (auto gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+	  for (auto gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 	    {
-	      stmt_vec_info stmt_info = vinfo->lookup_stmt (gsi_stmt (gsi));
+	      stmt_vec_info stmt_info = vinfo->lookup_stmt (gsi.phi ());
 	      if (stmt_info && STMT_VINFO_VECTORIZABLE (stmt_info))
 		vect_determine_mask_precision (vinfo, stmt_info);
 	    }
-	  for (auto gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+	  for (auto gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
 	    {
-	      stmt_vec_info stmt_info = vinfo->lookup_stmt (gsi.phi ());
+	      stmt_vec_info stmt_info = vinfo->lookup_stmt (gsi_stmt (gsi));
 	      if (stmt_info && STMT_VINFO_VECTORIZABLE (stmt_info))
 		vect_determine_mask_precision (vinfo, stmt_info);
 	    }
-- 
2.26.2